Glare refers to the phenomenon where, when light sources with high luminance and objects reflecting light are in sight, seeing objects becomes difficult because of the light entering the eyes (disability glare), or it is unpleasant to look at the objects because of the glare (discomfort glare).
Glare is a problem directly related to driver safety, and research into preventing such glare effects is actively underway in the automobile industry. Representative examples of glare include discomfort glare, disability glare, veiling reflection, etc.
Discomfort glare and disability glare denote that a much brighter object than the subject of interest is in sight. Thus, the bright object causes unpleasant feelings whenever the subject is observed, or the subject is not observed due to reduced sight sensitivity.
As an example of disability glare, at night, the light of the headlights of automobiles coming from an opposite direction may come into the sight of a driver and instantaneously stimulate the retinas of the driver, thereby causing temporary visual impairment. When driver safety is considered, disability glare must be prevented.
Veiling reflection denotes that light is overlapped with a subject by regular reflection or diffuse reflection. As an example of veiling reflection, a faint shape of a dashboard may be overlapped with the front glass of an automobile by light reflected from the dashboard of the automobile and thus the sight of the driver may be disturbed. Like disability glare, veiling reflection is also a problem that is directly related to driver safety and thus must be addressed.
Such glare is generally addressed by anti-reflective coating of automobile glass. In particular, in order to prevent glare, multiple coating layers are formed on a substrate and reflectivity is decreased by controlling a refractive index of each layer.
The prior art discloses a glass plate for automobiles including a reflectivity-reducing film having a two-layer structure. In the prior art, a refractive index of each layer of the film is varied, and veiling reflection is prevented by decreasing reflectivity of visible light illuminated to automobiles.
The prior art also discloses a transparent substrate including an anti-reflective coating. For example, a dielectric material having a high refractive index and a dielectric material having a low refractive index may be alternatively arranged in the anti-reflective coating to prevent glare by decreasing reflectivity.
Since glare is a problem that is directly related to driver safety as described above, further enhanced anti-reflective coating technology to completely address such a problem is required.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.